1. Field of the Invention
The present invention relates in general to a seat sliding device of a motor vehicle, and more particularly to a seat sliding device which comprises a stationary rail secured to the vehicle floor and a movable rail secured to the seat, the movable rail being slidable on and along the stationary rail to carry the seat in the fore-and-aft directions.
2. Description of the Prior Art
In order to provide the seat occupant (or driver) with a comfortable sitting position, seat sliding devices are widely used in a motor vehicle, which function to move the seat forward or rearward to a desired position. Some of these devices are of a type comprising a stationary metal rail secured to the vehicle floor and a movable metal rail secured to the seat. The movable rail slides on and along the stationary rail to achieve the forward or rearward movement of the seat relative to the vehicle floor. In such devices, a plastic slide block is attached to one of the two rails in a manner to be interposed between these two rails, for the purpose of improving the sliding characteristics of the movable rail relative to the stationary rail. Usually, the plastic slide block on the rail is provided by way of injection moulding using the selected rail as a core. The slide block thus moulded on the rail is inevitably formed to extend throughout the length of the rail. In other words, the rail has thereon and therethroughout an elongated slide block of plastics secured thereto.
However, in such a rail having the elongate plastic slide block, a peel off phenomenon of the slide block has sometimes occurred particularly in a cold season. Experiment has revealed that such undesirable phenomenon is caused by the difference in contractability between the plastic slide block and the metal rail. In fact, when exposed to a cold circumstance, the slide block is applied with a remarkable tensile stress because these two parts having different contractibilities are secured to each other. Thus, in the worst case, the slide block on the rail is broken deteriorating the sliding characteristics of the seat sliding device.